Sensors for detecting attachment to a surface are generally well known. For example, retail businesses that sell consumer goods, particularly expensive hand-held or portable electronic goods such as cameras, personal data assistants, laptop computers, calculators, camcorders, etc., use security sensors that detect removal of such an item from a point-of-purchase display area. The cable or tether enables a consumer to physically examine and test a hand-held, portable electronic product. The product is typically fixed to a tether or cable, which may be retractable, that enables the consumer to examine the product only in close proximity to the display area and prevents the consumer from removing the product from the display area. In some cases, the tether or cable provides power and/or other signals to the product. Often, the tether or cable also includes one or more wires or signal lines that connect to a security sensor at the product end of the tether or cable. Known security sensors are typically momentary switches encased in a housing that provide a push-button or the like protruding from an outer surface of the housing. Such push-button actuated security sensors are typically adhered via double-sided tape to a surface of the product being protected so that the push-button is depressed to maintain the switch contacts in a closed condition while the security sensor remains attached to the product. If the security sensor is removed from the product, the switch contacts move to an open condition.
Typically, the switch contacts are electrically connected to a remote security unit via signal lines traveling through the tether or cable. In the event the remote security unit detects that the switch contacts are in an electrically open condition (i.e., the current path between the contacts has been interrupted or broken), an alarm or other indication may be produced to alert security personnel, store managers, owners, etc. that a product may have been removed from the display area.
Unfortunately, retail theft of hand-held or portable electronic goods is a pervasive problem and the above-described known security sensors are relatively easy to circumvent or defeat. In general, known security sensors and switches use an attachment mechanism (e.g., double-sided tape) that is functionally independent from the switching or sensing mechanism. As a result of this functional independence, a thief can more easily disable or circumvent the switching or sensing mechanism before removing the security sensor from the product. For instance, a momentary switch-based security sensor that is attached to a product can be removed without detection by sliding a knife or other thin, flat object between the push-button and the product and using the knife or other object to maintain the push-button in a depressed or fully-actuated condition while removing the security sensor from the product.